1. Field of the Invention
The present invention relates to an optical packet switching system which enables packet switching for each optical packet by switching an optical switch according to routing information given to an optical packet signal.
2. Description of the Related Art
In optical transmission systems employing wavelength division multiplexing (WDM), a technique that performs the path switching per wavelength by the use of a wavelength selective switch (WSS) and the like is put to practical use. As a technology that may succeed this technique, an optical packet switching method is now being investigated. In this optical packet switching method, an IP packet (10 GEther (10 Gigabit Ethernet (registered trademark) signal and the like), for example, is used as a small unit with which the switching is performed, and each is converted into the form of an optical packet and then the route is switched by an ultrahigh-speed optical packet switching apparatus (see Reference (1) in the following Related Art List, for instance).
The IP packet does not transfer any significant information in the absence of data therein, so that the bandwidth corresponding thereto is wasted. However, if the optical packet switching system is realized, then the time slot of a packet where data is absent can be occupied by another packet. Therefore, the optical packet switching system is considered a promising technology of the future which is capable of markedly enhancing the bandwidth usage efficiency of the transmission path.
Related Art List    (1) Japanese Unexamined Patent Application Publication No. 2008-235986.
In this optical packet switching scheme, the bit error increases when the waveform of optical packet signal degrades on account of dispersion and non-linearity of optical transmission path. Yet, no structure or mechanism with which to monitor error is available in the conventional packet switching scheme. Thus arises a problem where the signal quality in optical transmission path cannot be monitored.